// 初始状态
let defaultState = {
        banners: []
    }
    // 化数组为一  生成唯一的当前状态  状态的改变 
const reducer = (state = defaultState, action) => {
    switch (action.type) {
        case 'CHANGE_BANNER':
            return {
                ...state,
                banners: action.data
            }
    }
    return state
}

export default reducer